Improve multipage (index) handling

src/main/java/net/sourceforge/plantuml/servlet/CheckSyntaxServlet.java

@@ -34,6 +34,7 @@ import jakarta.servlet.http.HttpServletResponse;
 
 import net.sourceforge.plantuml.FileFormat;
 import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
+import net.sourceforge.plantuml.servlet.utility.UrlDataExtractor;
 
 /**
  * Check servlet of the webapp.
@@ -46,7 +47,8 @@ public class CheckSyntaxServlet extends HttpServlet {
     public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
 
         // build the UML source from the compressed request parameter
-        String uml = UmlExtractor.getUmlSource(getSource(request.getRequestURI()));
+        final String url = request.getRequestURI();
+        final String uml = UmlExtractor.getUmlSource(UrlDataExtractor.getEncodedDiagram(url, ""));
 
         // generate the response
         DiagramResponse dr = new DiagramResponse(response, getOutputFormat(), request);
@@ -55,23 +57,6 @@ public class CheckSyntaxServlet extends HttpServlet {
         } catch (IIOException e) {
             // Browser has closed the connection, do nothing
         }
-        dr = null;
-    }
-
-    /**
-     * Extract UML source from URI.
-     *
-     * @param uri the complete URI as returned by `request.getRequestURI()`
-     *
-     * @return the encoded UML text
-     */
-    public String getSource(String uri) {
-        String[] result = uri.split("/check/", 2);
-        if (result.length != 2) {
-            return "";
-        } else {
-            return result[1];
-        }
     }
 
     /**

src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java

@@ -166,10 +166,14 @@ public class DiagramResponse {
      * Produce and send the image map of the uml diagram in HTML format.
      *
      * @param uml textual UML diagram source
+     * @param idx diagram index of {@code uml} to send
      *
      * @throws IOException if an input or output exception occurred
      */
-    public void sendMap(String uml) throws IOException {
+    public void sendMap(String uml, int idx) throws IOException {
+        if (idx < 0) {
+            idx = 0;
+        }
         response.setContentType(getContentType());
         SourceStringReader reader = new SourceStringReader(uml);
         final BlockUml blockUml = reader.getBlocks().get(0);
@@ -177,7 +181,7 @@ public class DiagramResponse {
             addHeaderForCache(blockUml);
         }
         final Diagram diagram = blockUml.getDiagram();
-        ImageData map = diagram.exportDiagram(new NullOutputStream(), 0,
+        ImageData map = diagram.exportDiagram(new NullOutputStream(), idx,
                 new FileFormatOption(FileFormat.PNG, false));
         if (map.containsCMapData()) {
             PrintWriter httpOut = response.getWriter();
@@ -237,7 +241,7 @@ public class DiagramResponse {
      *
      * @param response http response
      */
-    public static void addHeaders(HttpServletResponse response) {
+    private static void addHeaders(HttpServletResponse response) {
         response.addHeader("X-Powered-By", POWERED_BY);
         response.addHeader("X-Patreon", "Support us on https://plantuml.com/patreon");
         response.addHeader("X-Donate", "https://plantuml.com/paypal");

src/main/java/net/sourceforge/plantuml/servlet/MapServlet.java

@@ -34,6 +34,7 @@ import jakarta.servlet.http.HttpServletResponse;
 
 import net.sourceforge.plantuml.FileFormat;
 import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
+import net.sourceforge.plantuml.servlet.utility.UrlDataExtractor;
 
 /**
  * MAP servlet of the webapp.
@@ -46,32 +47,17 @@ public class MapServlet extends HttpServlet {
     public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
 
         // build the UML source from the compressed request parameter
-        String uml = UmlExtractor.getUmlSource(getSource(request.getRequestURI()));
+        final String url = request.getRequestURI();
+        final String uml = UmlExtractor.getUmlSource(UrlDataExtractor.getEncodedDiagram(url, ""));
+        final int idx = UrlDataExtractor.getIndex(url, 0);
 
         // generate the response
         DiagramResponse dr = new DiagramResponse(response, getOutputFormat(), request);
         try {
-            dr.sendMap(uml);
+            dr.sendMap(uml, idx);
         } catch (IIOException e) {
             // Browser has closed the connection, do nothing
         }
-        dr = null;
-    }
-
-    /**
-     * Extract UML source from URI.
-     *
-     * @param uri the complete URI as returned by `request.getRequestURI()`
-     *
-     * @return the encoded UML text
-     */
-    public String getSource(String uri) {
-        String[] result = uri.split("/map/", 2);
-        if (result.length != 2) {
-            return "";
-        } else {
-            return result[1];
-        }
     }
 
     /**

src/main/java/net/sourceforge/plantuml/servlet/PlantUmlServlet.java

@@ -45,6 +45,7 @@ import net.sourceforge.plantuml.code.TranscoderUtil;
 import net.sourceforge.plantuml.png.MetadataTag;
 import net.sourceforge.plantuml.servlet.utility.Configuration;
 import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
+import net.sourceforge.plantuml.servlet.utility.UrlDataExtractor;
 
 /**
  * Original idea from Achim Abeling for Confluence macro.
@@ -69,10 +70,6 @@ public class PlantUmlServlet extends HttpServlet {
      * Regex pattern to fetch last part of the URL.
      */
     private static final Pattern URL_PATTERN = Pattern.compile("^.*[^a-zA-Z0-9\\-\\_]([a-zA-Z0-9\\-\\_]+)");
-    /**
-     * Regex pattern to fetch encoded uml text from an "uml" URL.
-     */
-    private static final Pattern RECOVER_UML_PATTERN = Pattern.compile("/uml/(.*)");
 
     static {
         OptionFlags.ALLOW_INCLUDE = false;
@@ -94,8 +91,11 @@ public class PlantUmlServlet extends HttpServlet {
             return;
         }
 
+        // diagram index to render
+        final int idx = UrlDataExtractor.getIndex(request.getRequestURI());
+
         // forward to index.jsp
-        prepareRequestForDispatch(request, text);
+        prepareRequestForDispatch(request, text, idx);
         final RequestDispatcher dispatcher = request.getRequestDispatcher("/index.jsp");
         dispatcher.forward(request, response);
     }
@@ -107,6 +107,9 @@ public class PlantUmlServlet extends HttpServlet {
     ) throws ServletException, IOException {
         request.setCharacterEncoding("UTF-8");
 
+        // diagram index to render
+        final int idx = UrlDataExtractor.getIndex(request.getRequestURI());
+
         // encoded diagram source
         String encoded;
         try {
@@ -117,7 +120,7 @@ public class PlantUmlServlet extends HttpServlet {
             e.printStackTrace();
         }
 
-        redirectNow(request, response, encoded);
+        redirectNow(request, response, encoded, idx);
     }
 
     /**
@@ -174,15 +177,16 @@ public class PlantUmlServlet extends HttpServlet {
      * @throws IOException if an input or output exception occurred
      */
     private String getTextFromUrl(HttpServletRequest request) throws IOException {
-        final Matcher recoverUml = RECOVER_UML_PATTERN.matcher(
+        // textual diagram source from request URI
-            request.getRequestURI().substring(request.getContextPath().length())
+        String url = request.getRequestURI();
-        );
+        if (url.contains("/uml/") && !url.endsWith("/uml/")) {
-        // the URL form has been submitted
+            final String encoded = UrlDataExtractor.getEncodedDiagram(request.getRequestURI(), "");
-        if (recoverUml.matches()) {
+            if (!encoded.isEmpty()) {
-            final String data = recoverUml.group(1);
+                return getTranscoder().decode(encoded);
-            return getTranscoder().decode(data);
+            }
         }
-        String url = request.getParameter("url");
+        // textual diagram source from "url" parameter
+        url = request.getParameter("url");
         if (url != null && !url.trim().isEmpty()) {
             // Catch the last part of the URL if necessary
             final Matcher matcher = URL_PATTERN.matcher(url);
@@ -203,11 +207,12 @@ public class PlantUmlServlet extends HttpServlet {
      *
      * @throws IOException if an input or output exception occurred
      */
-    private void prepareRequestForDispatch(HttpServletRequest request, String text) throws IOException {
+    private void prepareRequestForDispatch(HttpServletRequest request, String text, int idx) throws IOException {
-        // diagram sources
         final String encoded = getTranscoder().encode(text);
+        final String index = (idx < 0) ? "" : idx + "/";
+        // diagram sources
         request.setAttribute("decoded", text);
-        request.setAttribute("encoded", encoded);
+        request.setAttribute("index", idx);
         // properties
         request.setAttribute("showSocialButtons", Configuration.get("SHOW_SOCIAL_BUTTONS"));
         request.setAttribute("showGithubRibbon", Configuration.get("SHOW_GITHUB_RIBBON"));
@@ -217,10 +222,10 @@ public class PlantUmlServlet extends HttpServlet {
         // image URLs
         final boolean hasImg = !text.isEmpty();
         request.setAttribute("hasImg", hasImg);
-        request.setAttribute("imgurl", hostpath + "/png/" + encoded);
+        request.setAttribute("imgurl", hostpath + "/png/" + index + encoded);
-        request.setAttribute("svgurl", hostpath + "/svg/" + encoded);
+        request.setAttribute("svgurl", hostpath + "/svg/" + index + encoded);
-        request.setAttribute("txturl", hostpath + "/txt/" + encoded);
+        request.setAttribute("txturl", hostpath + "/txt/" + index + encoded);
-        request.setAttribute("mapurl", hostpath + "/map/" + encoded);
+        request.setAttribute("mapurl", hostpath + "/map/" + index + encoded);
         // map for diagram source if necessary
         final boolean hasMap = PlantumlUtils.hasCMapData(text);
         request.setAttribute("hasMap", hasMap);
@@ -276,7 +281,32 @@ public class PlantUmlServlet extends HttpServlet {
         HttpServletResponse response,
         String encoded
     ) throws IOException {
-        final String result = request.getContextPath() + "/uml/" + encoded;
+        redirectNow(request, response, encoded, null);
+    }
+
+    /**
+     * Send redirect response to encoded uml text.
+     *
+     * @param request http request
+     * @param response http response
+     * @param encoded encoded uml text
+     * @param index diagram index
+     *
+     * @throws IOException if an input or output exception occurred
+     */
+    private void redirectNow(
+        HttpServletRequest request,
+        HttpServletResponse response,
+        String encoded,
+        Integer index
+    ) throws IOException {
+        final String result;
+        if (index == null || index < 0) {
+            result = request.getContextPath() + "/uml/" + encoded;
+        } else {
+            result = request.getContextPath() + "/uml/" + index + "/" + encoded;
+        }
+
         response.sendRedirect(result);
     }
 

src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java

@@ -25,8 +25,6 @@ package net.sourceforge.plantuml.servlet;
 
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 import javax.imageio.IIOException;
 
@@ -34,9 +32,11 @@ import jakarta.servlet.ServletException;
 import jakarta.servlet.http.HttpServlet;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
+
 import net.sourceforge.plantuml.FileFormat;
 import net.sourceforge.plantuml.OptionFlags;
 import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
+import net.sourceforge.plantuml.servlet.utility.UrlDataExtractor;
 
 /**
  * Common service servlet to produce diagram from compressed UML source contained in the end part of the requested URI.
@@ -44,11 +44,6 @@ import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
 @SuppressWarnings("SERIAL")
 public abstract class UmlDiagramService extends HttpServlet {
 
-    /**
-     * Regex pattern to fetch encoded uml text from an URL.
-     */
-    private static final Pattern RECOVER_UML_PATTERN = Pattern.compile("/\\w+/(\\d+/)?(.*)");
-
     static {
         OptionFlags.ALLOW_INCLUDE = false;
         if ("true".equalsIgnoreCase(System.getenv("ALLOW_PLANTUML_INCLUDE"))) {
@@ -58,12 +53,14 @@ public abstract class UmlDiagramService extends HttpServlet {
 
     @Override
     public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
+        final String url = request.getRequestURI();
+        final String encoded = UrlDataExtractor.getEncodedDiagram(url, "");
+        final int idx = UrlDataExtractor.getIndex(url, 0);
+
         // build the UML source from the compressed request parameter
-        final String[] sourceAndIdx = getSourceAndIdx(request);
-        final int idx = Integer.parseInt(sourceAndIdx[1]);
         final String uml;
         try {
-            uml = UmlExtractor.getUmlSource(sourceAndIdx[0]);
+            uml = UmlExtractor.getUmlSource(encoded);
         } catch (Exception e) {
             e.printStackTrace();
             response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Bad Request");
@@ -75,18 +72,15 @@ public abstract class UmlDiagramService extends HttpServlet {
 
     @Override
     public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
-        // build the UML source from the compressed request parameter
+        final int idx = UrlDataExtractor.getIndex(request.getRequestURI(), 0);
-        final String[] sourceAndIdx = getSourceAndIdx(request);
-        final int idx = Integer.parseInt(sourceAndIdx[1]);
 
+        // read textual diagram source from request body
         final StringBuilder uml = new StringBuilder();
-        final BufferedReader in = request.getReader();
+        try (BufferedReader in = request.getReader()) {
-        while (true) {
+            String line;
-            final String line = in.readLine();
+            while ((line = in.readLine()) != null) {
-            if (line == null) {
+                uml.append(line).append('\n');
-                break;
             }
-            uml.append(line).append('\n');
         }
 
         doDiagramResponse(request, response, uml.toString(), idx);
@@ -118,33 +112,6 @@ public abstract class UmlDiagramService extends HttpServlet {
         }
     }
 
-    /**
-     * Extracts the UML source text and its index from the HTTP request.
-     *
-     * @param request http request
-     *
-     * @return the UML source text and its index
-     */
-    public final String[] getSourceAndIdx(HttpServletRequest request) {
-        final Matcher recoverUml = RECOVER_UML_PATTERN.matcher(
-            request.getRequestURI().substring(
-            request.getContextPath().length()));
-        // the URL form has been submitted
-        if (recoverUml.matches()) {
-            final String data = recoverUml.group(2);
-            if (data.length() >= 4) {
-                String idx = recoverUml.group(1);
-                if (idx == null) {
-                    idx = "0";
-                } else {
-                    idx = idx.substring(0, idx.length() - 1);
-                }
-                return new String[]{data, idx };
-            }
-        }
-        return new String[]{"", "0"};
-    }
-
     /**
      * Gives the wished output format of the diagram. This value is used by the DiagramResponse class.
      *

src/main/java/net/sourceforge/plantuml/servlet/diagrams.txt

@@ -6,26 +6,33 @@ hide empty members
 hide empty methods
 hide empty fields
 abstract class UmlDiagramService {
-  public void doGet(HttpServletRequest rq, HttpServletResponse rsp)
+  + doGet(request: HttpServletRequest, response: HttpServletResponse) : void
-  abstract public String getSource( String uri)
+  + doPost(request: HttpServletRequest, response: HttpServletResponse) : void
-  abstract FileFormat getOutputFormat()
+  + {abstract} getOutputFormat() : FileFormat
 }
 class DiagramResponse {
-  DiagramResponse( HttpServletResponse r, FileFormat f)
+  + DiagramResponse(res: HttpServletResponse, fmt: FileFormat, req: HttpServletRequest)
-  void sendDiagram( String uml)
+  + sendDiagram(uml: String, idx: int) : void
-  void sendMap( String uml)
+  + sendMap(uml: String, idx: int) : void
+  + sendCheck(uml: String) : void
 }
-abstract HttpServlet <|-- UmlDiagramService
+HttpServlet <|-- CheckSyntaxServlet
-abstract HttpServlet <|-- MapServlet
+HttpServlet <|-- LanguageServlet
-abstract HttpServlet <|-- ProxyServlet
+HttpServlet <|-- MapServlet
-UmlDiagramService <|-- PngServlet
+HttpServlet <|-- PlantUmlServlet
-UmlDiagramService <|-- SvgServlet
+HttpServlet <|-- ProxyServlet
+HttpServlet <|-- OldProxyServlet
+HttpServlet <|-- UmlDiagramService
+UmlDiagramService <|-- AsciiServlet
+UmlDiagramService <|-- Base64Servlet
 UmlDiagramService <|-- EpsServlet
 UmlDiagramService <|-- EpsTextServlet
-UmlDiagramService <|-- AsciiServlet
+UmlDiagramService <|-- ImgServlet
-UmlDiagramService o- DiagramResponse
+UmlDiagramService <|-- SvgServlet
-MapServlet o-- DiagramResponse
+UmlDiagramService o-- DiagramResponse
-ProxyServlet o-- DiagramResponse
+DiagramResponse --o CheckSyntaxServlet
+DiagramResponse --o MapServlet
+DiagramResponse --o ProxyServlet
 @enduml
 
 ## Sequence diagram ##
@@ -33,14 +40,17 @@ ProxyServlet o-- DiagramResponse
 
 @startuml
 title Generation of a PNG image illustrated
-PngServlet -> PngServlet : getSource()
+ImgServlet -> UrlDataExtractor : getEncodedDiagram()
-PngServlet -> UmlExtractor : getUmlSource()
+UrlDataExtractor --> ImgServlet : encoded
-UmlExtractor --> PngServlet
+ImgServlet -> UrlDataExtractor : getIndex()
-PngServlet -> PngServlet : getOutputFormat()
+UrlDataExtractor --> ImgServlet : index
-PngServlet -> DiagramResponse : <<create>>
+ImgServlet -> UmlExtractor : getUmlSource()
-PngServlet -> DiagramResponse : sendDiagram()
+UmlExtractor --> ImgServlet : decoded
+ImgServlet -> ImgServlet : getOutputFormat()
+ImgServlet -> "dr:DiagramResponse" as dr ** : <<create>>
+ImgServlet -> dr : sendDiagram()
 participant "PlantUML library" as Lib #99FF99
-DiagramResponse -> Lib : generateImage()
+dr -> Lib : generateImage()
-Lib --> DiagramResponse
+Lib --> dr
-DiagramResponse --> PngServlet
+dr --> ImgServlet
 @enduml

src/main/java/net/sourceforge/plantuml/servlet/utility/UrlDataExtractor.java

@@ -0,0 +1,102 @@
+/* ========================================================================
+ * PlantUML : a free UML diagram generator
+ * ========================================================================
+ *
+ * Project Info:  https://plantuml.com
+ *
+ * This file is part of PlantUML.
+ *
+ * PlantUML is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PlantUML distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA.
+ */
+package net.sourceforge.plantuml.servlet.utility;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Utility class to extract the index and diagram source from an URL, e.g., returned by `request.getRequestURI()`.
+ */
+public abstract class UrlDataExtractor {
+
+    /**
+     * URL regex pattern to easily extract index and encoded diagram.
+     */
+    private static final Pattern URL_PATTERN = Pattern.compile(
+        "/\\w+(?:/(?<idx>\\d+))?(?:/(?<encoded>[^/]+))?/?$"
+    );
+
+    /**
+     * Get diagram index from URL.
+     *
+     * @param url URL to analyse, e.g., returned by `request.getRequestURI()`
+     *
+     * @return if exists diagram index; otherwise -1
+     */
+    public static int getIndex(final String url) {
+        return getIndex(url, -1);
+    }
+
+    /**
+     * Get diagram index from URL.
+     *
+     * @param url URL to analyse, e.g., returned by `request.getRequestURI()`
+     * @param fallback fallback index if no index exists in {@code url}
+     *
+     * @return if exists diagram index; otherwise {@code fallback}
+     */
+    public static int getIndex(final String url, final int fallback) {
+        final Matcher matcher = URL_PATTERN.matcher(url);
+        if (!matcher.find()) {
+            return fallback;
+        }
+        String idx = matcher.group("idx");
+        if (idx == null) {
+            return fallback;
+        }
+        return Integer.parseInt(idx);
+    }
+
+    /**
+     * Get encoded diagram source from URL.
+     *
+     * @param url URL to analyse, e.g., returned by `request.getRequestURI()`
+     *
+     * @return if exists diagram index; otherwise `null`
+     */
+    public static String getEncodedDiagram(final String url) {
+        return getEncodedDiagram(url, null);
+    }
+
+    /**
+     * Get encoded diagram source from URL.
+     *
+     * @param url URL to analyse, e.g., returned by `request.getRequestURI()`
+     * @param fallback fallback if no encoded diagram source exists in {@code url}
+     *
+     * @return if exists diagram index; otherwise {@code fallback}
+     */
+    public static String getEncodedDiagram(final String url, final String fallback) {
+        final Matcher matcher = URL_PATTERN.matcher(url);
+        if (!matcher.find()) {
+            return fallback;
+        }
+        String encoded = matcher.group("encoded");
+        if (encoded == null) {
+            return fallback;
+        }
+        return encoded;
+    }
+}

src/main/webapp/index.jsp

@@ -3,7 +3,6 @@
 <%
     // diagram sources
     String decoded = request.getAttribute("decoded").toString();
-    String encoded = request.getAttribute("encoded").toString();
     // properties
     boolean showSocialButtons = (boolean)request.getAttribute("showSocialButtons");
     boolean showGithubRibbon = (boolean)request.getAttribute("showGithubRibbon");

src/test/java/net/sourceforge/plantuml/servlet/TestForm.java

@@ -216,4 +216,88 @@ public class TestForm extends WebappTestCase {
         }
     }
 
+    /**
+     * Verifies that an multipage diagram renders correct given index.
+     *
+     * Bob -> Alice : hello
+     * newpage
+     * Bob <- Alice : hello
+     * Bob -> Alice : let's talk
+     * Bob <- Alice : better not
+     * Bob -> Alice : <&rain> bye
+     * newpage
+     * Bob <- Alice : bye
+     */
+    public void testIndexPage() throws IOException {
+        try (final WebClient webClient = new WebClient()) {
+            HtmlPage page = webClient.getPage(
+                getServerUrl() + "/uml/1/" +
+                "SyfFKj2rKt3CoKnELR1Io4ZDoSddoaijBqXCJ-Lo0ahQwA99Eg7go4ajKIzMA4dCoKPNdfHQKf9Qf92NNuAknqQjA34ppquXgJ8Lbrr0AG00"
+            );
+            // Analyze response
+            List<HtmlForm> forms = page.getForms();
+            assertEquals(2, forms.size());
+            // Ensure the Text field is correct
+            String text = ((HtmlTextArea)(forms.get(0).getFirstByXPath("//textarea[contains(@name, 'text')]"))).getTextContent();
+            assertEquals(
+                "@startuml\nBob -> Alice : hello\nnewpage\nBob <- Alice : hello\nBob -> Alice : let's talk\nBob <- Alice : better not\nBob -> Alice : <&rain> bye\nnewpage\nBob <- Alice : bye\n@enduml",
+                text
+            );
+            // Ensure the URL field is correct
+            HtmlInput url = forms.get(1).getInputByName("url");
+            assertNotNull(url);
+            assertTrue(url.getAttribute("value").endsWith("/png/1/SyfFKj2rKt3CoKnELR1Io4ZDoSddoaijBqXCJ-Lo0ahQwA99Eg7go4ajKIzMA4dCoKPNdfHQKf9Qf92NNuAknqQjA34ppquXgJ8Lbrr0AG00"));
+            // Ensure the generated image is present
+            HtmlImage img = page.getFirstByXPath("//img[contains(@alt, 'PlantUML diagram')]");
+            int height = img.getImageReader().getHeight(0);
+            assertNotEquals(0, height);  // 222
+            assertNotEquals(0, img.getImageReader().getWidth(0));  // 152
+            // Ensure the correct index was generated
+            assertTrue(height > 200);  // 222
+            assertTrue(height < 250);  // 222
+        }
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct even if no index is specified.
+     *
+     * Bob -> Alice : hello
+     * newpage
+     * Bob <- Alice : hello
+     * Bob -> Alice : let's talk
+     * Bob <- Alice : better not
+     * Bob -> Alice : <&rain> bye
+     * newpage
+     * Bob <- Alice : bye
+     */
+    public void testIndexPageWithNoDefinedIndex() throws IOException {
+        try (final WebClient webClient = new WebClient()) {
+            HtmlPage page = webClient.getPage(
+                getServerUrl() + "/uml/" +
+                "SyfFKj2rKt3CoKnELR1Io4ZDoSddoaijBqXCJ-Lo0ahQwA99Eg7go4ajKIzMA4dCoKPNdfHQKf9Qf92NNuAknqQjA34ppquXgJ8Lbrr0AG00"
+            );
+            // Analyze response
+            List<HtmlForm> forms = page.getForms();
+            assertEquals(2, forms.size());
+            // Ensure the Text field is correct
+            String text = ((HtmlTextArea)(forms.get(0).getFirstByXPath("//textarea[contains(@name, 'text')]"))).getTextContent();
+            assertEquals(
+                "@startuml\nBob -> Alice : hello\nnewpage\nBob <- Alice : hello\nBob -> Alice : let's talk\nBob <- Alice : better not\nBob -> Alice : <&rain> bye\nnewpage\nBob <- Alice : bye\n@enduml",
+                text
+            );
+            // Ensure the URL field is correct
+            HtmlInput url = forms.get(1).getInputByName("url");
+            assertNotNull(url);
+            assertTrue(url.getAttribute("value").endsWith("/png/SyfFKj2rKt3CoKnELR1Io4ZDoSddoaijBqXCJ-Lo0ahQwA99Eg7go4ajKIzMA4dCoKPNdfHQKf9Qf92NNuAknqQjA34ppquXgJ8Lbrr0AG00"));
+            // Ensure the generated image is present
+            HtmlImage img = page.getFirstByXPath("//img[contains(@alt, 'PlantUML diagram')]");
+            int height = img.getImageReader().getHeight(0);
+            assertNotEquals(0, height);  // 132
+            assertNotEquals(0, img.getImageReader().getWidth(0));  // 152
+            // Ensure the correct index was generated
+            assertTrue(height > 100);  // 132
+            assertTrue(height < 150);  // 132
+        }
+    }
+
 }

src/test/java/net/sourceforge/plantuml/servlet/TestMultipageUml.java

@@ -0,0 +1,199 @@
+package net.sourceforge.plantuml.servlet;
+
+import static org.junit.Assert.assertNotEquals;
+
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLConnection;
+
+
+public class TestMultipageUml extends WebappTestCase {
+
+    /**
+     * Encoded/compressed diagram source to text multipage uml diagrams.
+     * 
+     * Bob -> Alice : hello
+     * newpage
+     * Bob <- Alice : hello
+     * Bob -> Alice : let's talk [[tel:0123456789]]
+     * Bob <- Alice : better not
+     * Bob -> Alice : <&rain> bye
+     * newpage
+     * Bob <- Alice : bye
+     */
+    private static final String ENCODED = "SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKiX8pSd9vyfBBIz8J4y5IzheeagYwyX9BL4lLYX9pCbMY8ukISsnCZ0qCZOnDJEti8oDHJSXARMa9BL88I-_1DqO6xMYnCmyEuMaobGSreEb75BpKe3E1W00";
+
+    /**
+     * Verifies that an multipage diagram renders correct given index (PNG).
+     */
+    public void testPngIndexPage() throws IOException {
+        final URL url = new URL(getServerUrl() + "/png/1/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not PNG",
+            "image/png",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the image and verify its size
+        byte[] inMemoryImage = getContentAsBytes(conn);
+        int diagramLen = inMemoryImage.length;  // 7525
+        assertTrue(diagramLen > 6000);
+        assertTrue(diagramLen < 9000);
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct even if no index is specified (PNG).
+     */
+    public void testPngIndexPageNoIndex() throws IOException {
+        final URL url = new URL(getServerUrl() + "/png/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not PNG",
+            "image/png",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the image and verify its size
+        byte[] inMemoryImage = getContentAsBytes(conn);
+        int diagramLen = inMemoryImage.length;  // 4196
+        assertTrue(diagramLen > 3000);
+        assertTrue(diagramLen < 5000);
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct given index (SVG).
+     */
+    public void testSvgIndexPage() throws IOException {
+        final URL url = new URL(getServerUrl() + "/svg/1/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not SVG",
+            "image/svg+xml",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the content and verify its size
+        String diagram = getContentText(conn);
+        int diagramLen = diagram.length();  // 5834
+        assertTrue(diagramLen > 5500);
+        assertTrue(diagramLen < 7000);
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct even if no index is specified (SVG).
+     */
+    public void testSvgIndexPageNoIndex() throws IOException {
+        final URL url = new URL(getServerUrl() + "/svg/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not SVG",
+            "image/svg+xml",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the content and verify its size
+        String diagram = getContentText(conn);
+        int diagramLen = diagram.length();  // 2970
+        assertTrue(diagramLen > 1500);
+        assertTrue(diagramLen < 4000);
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct given index (AsciiArt).
+     */
+    public void testAsciiArtIndexPage() throws IOException {
+        final URL url = new URL(getServerUrl() + "/txt/1/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not TEXT PLAIN or UTF-8",
+            "text/plain;charset=utf-8",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the content and verify its size
+        String diagram = getContentText(conn);
+        int diagramLen = diagram.length();
+        assertNotEquals(0, diagramLen);
+        // BUG/Missing Feature: plantuml renders always whole AsciiArt diagram
+        //assertTrue(diagramLen > ??);
+        //assertTrue(diagramLen < ??);
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct even if no index is specified (AsciiArt).
+     */
+    public void testAsciiArtIndexPageNoIndex() throws IOException {
+        final URL url = new URL(getServerUrl() + "/txt/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not TEXT PLAIN or UTF-8",
+            "text/plain;charset=utf-8",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the content and verify its size
+        String diagram = getContentText(conn);
+        int diagramLen = diagram.length();
+        assertNotEquals(0, diagramLen);
+        // BUG/Missing Feature: plantuml renders always whole AsciiArt diagram
+        //assertTrue(diagramLen > ??);
+        //assertTrue(diagramLen < ??);
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct given index (Map).
+     */
+    public void testMapIndexPage() throws IOException {
+        final URL url = new URL(getServerUrl() + "/map/1/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not TEXT PLAIN or UTF-8",
+            "text/plain;charset=utf-8",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the data contained in the XML
+        String map = getContentText(url);
+        // map contains "tel:0123456789"
+        assertTrue(
+            "Response does not contain 'tel:0123456789'",
+            map.contains("tel:0123456789")
+        );
+        // Verify shape:
+        // <map id="..." name="...">
+        // <area shape="..." id="..." href="..." ... />
+        // </map>
+        assertTrue(
+            "Response doesn't match shape",
+            map.matches("^<map id=\".+\" name=\".+\">\n(<area shape=\".+\" id=\".+\" href=\".+\".*/>\n)</map>\n*$")
+        );
+    }
+
+    /**
+     * Verifies that an multipage diagram renders correct even if no index is specified (Map).
+     */
+    public void testMapIndexPageNoIndex() throws IOException {
+        final URL url = new URL(getServerUrl() + "/map/" + ENCODED);
+        final URLConnection conn = url.openConnection();
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals(
+            "Response content type is not TEXT PLAIN or UTF-8",
+            "text/plain;charset=utf-8",
+            conn.getContentType().toLowerCase()
+        );
+        // Get the data contained in the XML
+        String diagram = getContentText(conn);
+        int diagramLen = diagram.length();
+        assertEquals(0, diagramLen);
+    }
+
+}